Many parts of the body are inaccessible unless risky and highly invasive surgery is performed. Other bodily regions are reachable via vascular, digestive, reproductive, or other biological lumens, but are inaccessible to interventional methods due to biological parameters and the state of current tooling. Other surgical sites can be accessed directly (i.e., not intravascularly), but it is desired to reliably position the surgical instrument at a specific orientation with respect to the target anatomical location in situations that make the use of conventional surgical tooling difficult.
Basic deflection systems came into practice to give physicians control of remote tubing and surgical tools for various vascular and non-vascular applications that are out of reach for hand based operations. Initial steering systems used pull wires to manipulate a given tubular structure and produce deflection of the elongated tube. Such a bend allowed for vessel navigation, and directional pointingly for a tool or procedure function. The pull wire system began as one wire for single plane deflection. With better deflectable tubing and smaller pull wires, more than one pull wire have been installed into systems to allow for two plane deflection, and in some cases multi-plane deflection. Given the size required by mechanical wires to achieve more than one or two planes of deflection, most multi plane systems have usually been limited to robotic systems, large medical devices, and a large number of non-medical cameras and deflectable tubing primarily in the aerospace and industrial engineering sectors. At the same time, most bi-direction and omnidirectional (4 way) systems have relied on rotation along the central axis to torque steer the fixed deflection planes into new positions, which requires overcoming the resistance of tissues in contact with the length of deployed tubing.
Non-medical ceramics and materials research grew on a nearly adjacent timeline. Piezoelectric ceramics were visualized as alternate actuators to deflect medical tubing. Their application was limited by the degree of deflection allowed by their relatively high young's modulus. A similar alternative actuator, most notably Nitinol based materials, were used to replace mechanical pull wires as they were subsequently developed for other structural medical devices. However, Nitinol based deflection systems are not optimal due to their high temperature output and other factors.